#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef pair<int, int> pii;
const int mod = 1e9 + 7;

int gcd(int a, int b)
{
    return b ? gcd(b, a % b) : a;
}

ll qmi(ll a, ll b)
{
    ll res = 1;
    while(b)
    {
        if(b & 1)res = res * a % mod;
        b >>= 1;
        a = a * a % mod;
    }
    return res;
}
struct custom_hash {
	static uint64_t splitmix64(uint64_t x) {
		x ^= x << 13;
		x ^= x >> 7;
		x ^= x << 17;
		return x; 
	}
	size_t operator () (uint64_t x) const {
		static const uint64_t FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count(); // 时间戳
		return splitmix64(x + FIXED_RANDOM);
	}
};


int main()
{
    int n, m;
    cin >> n >> m;
    vector<int> a(n), b(m);
    for(int i = 0; i < n; i++) cin >> a[i];
    for(int i = 0; i < m; i++) cin >> b[i];
    sort(a.begin(), a.end());
    sort(b.begin(), b.end());
    int i = 0, j = 0;
    int ans = INT_MAX;
    while(i < n && j < m)
    {
        ans = min(ans, abs(a[i] - b[j]));
        if(a[i] > b[j]) j++;
        else i++;
    }       
    cout << ans << endl;
    return 0;
}